This invention relates generally to lubrication devices and apparatus and more particularly to devices and apparatus for lubricating sheathed cables.
Sheathed cables for the transmission of rotary motion are commonly utilized in numerous apparatus and machines. For example sheathed rotary cables are used in automobiles to connect the transmission of the automobile to the speedometer which is mounted in the dashboard. Such cables are referred to as speedometer cables and consist of an elongated flexible cable element or wire disposed within the flexible sheath. The cable element is arranged to rotate within the sheath under the rotary force provided by the transmission when the automobile is in motion. Because of the length of of the speedometer cable, e.g., several feet, and the fact that the cable with its sheath normally follows a circuitous path from the transmission on the underside of the automobile frame to the interior of the dashboard, there is a great deal of frictional contact between the cable and the inside surface of the sheath as the cable rotates. This frictional contact requires the maintenance of a good lubrication between the sheath and cable to prevent any friction-induced noise or cable damage. Thus, it is highly desirable to lubricate the cable-sheath interface of the speedometer cable among routine maintenance operations performed on the automobile. Despite the desirability of such action, it has heretofore been neglected due to the difficulty and inconvenience of accomplishing it.
In this regard one prior art technique for effecting lubrication of a cable involves disconnecting the cable and sheath from the automobile speedometer and transmission so that the cable can be completely withdrawn from the sheath. After withdrawal of the cable it is lubricated by applying grease to its surface along its entire length and thereafter reinserting it into the sheath. The sheath with the cable is then repositioned in the automobile and reconnected. Obviously such a procedure is quite time consuming and therefore expensive. Moreover, the speedometer end of the speedometer cable is frequently located under the dashboard of the automobile in a relatively inaccessible position. Thus, the disconnection of the sheath and cable from the speedometer unit is also a time consuming operation. In fact in many cases such an operation necessitates the disassembly of various portions of the dashboard which may block access to the cable.
Further still, the withdrawal of the cable often requires that its sheath, with the cable still in it, be withdrawn from its normal position between the transmission and the speedometer because a bend or curved portion of the cable sheath resists the withdrawal action. Therefore, the sheath and the cable frequently have to be snaked out of their normal positions within the maze of other cabling and wiring under the dashboard and more less straightened before the cable can be withdrawn from the sheath. The reinsertion process of the cable into the sheath is at least as difficult inasmuch as the curved sheath resists cable insertion. This latter factor is another reason why it is often necessary to snake the sheath out from its normal position within the automobile for lubricating purposes.
The above described lubricating difficulties are so severe that as a result thereof speedometer cable lubrication is one of the most frequently neglected aspects of automotive service.
Heretofore I have found that one technique for obviating the above described problems in lubricating speedometer cables has been to disconnect the transmission end of the speedometer cable and to utilize a grease or oil injection tool or coupling which is configured to be connected to all types of fittings on the transmission end of the cable sheath and which is arranged to be mounted on a conventional grease gun or oil can. The grease or oil can then be manually pumped into the space between the cable and the sheath without requiring the complete removal of the cable from the sheath or the removal of the sheath from the automobile. This "in-position" lubrication technique offered substantial time and labor saving advantages over techniques requiring disassembly and removal of the cable/sheath.
Dorman Products, Inc. of Cincinnati, Ohio sells lubrication tools or adapters under the model designations 486-950, 486-951 and 486-952 which are arranged to be mounted on a conventional hand held grease gun. The tool is then connected to the fitting on the transmission end of the speedometer cable to lubricate the cable using the above described in-position technique.
In U.S. Pat. No. 3,884,329 (Steffen) there is shown a speedometer lubricating device which comprises a pressure oil can having a housing to receive lubricating oil and a push button actuator which upon reciprocation by a pumping action causes the oil to be delivered under pressure to a discharge fitting and from there into the transmission end of the speedometer cable.
While the use of prior art techniques, adapters and tools, such as that described above utilizing pressurized oil cans or grease guns, for in-position speedometer cable lubrication offer advantages over lubrication techniques involving cable and/or sheath removal, such in-position lubrication techniques still leave much to be desired from the standpoint of effectiveness and efficiency of lubrication. In this connection the grease or oil which is manually injected by the grease gun or oil can into the space between the cable and the sheath tends to remain toward the transmission end of the cable instead of extending and flowing throughout the whole length of the cable.